Medscape 

Overall, adverse event rates are comparable between the two vaccines, although injection-site AEs are more common with the 9-valent human papillomavirus vaccine (9vHPV) (Gardasil 9, Merck & Co., Inc.) than with the quadrivalent HPV (qHPV) vaccine (Gardasil, Merck & Co., Inc.), and they increase with subsequent doses for both vaccines, a new analysis concludes. 

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